eVENT Willis Research Network Hurricane Commentary

Hurricane Matthew Executive Summary Matthew is maintaining major hurricane status as it tracks north through the Greater Antilles. A line of thunderstorms thrown out ahead of the storm heralded Matthew’s arrival last night in the Greater Antilles. Ingredients will be in place for Matthew to maintain major hurricane status as it continues north. Hurricane impacts are possible anywhere from Florida to Maine and interests along the U.S. East Coast should monitor developments.

Date/Time 5:00 p.m. EDT Oct 3, 2016 Location 16.3N, 74.7W Windspeed/Pressure 140mph, 940mb (Cat 4) Speed/Direction 7mph N

Forecast Summary Matthew’s rapid intensification over the weekend caught many by surprise, and ended a nine-year stretch since the previous Category 5 North Atlantic hurricane - Felix in 2007. Although hinted at by some forecast models, explosive deepening was considered an outside possibility. Was it caused by the unusual clump of thunderstorms to the east of Matthew, or was it the moisture-laden environment, or perhaps Matthew’s small eye? Whatever the cause, Matthew is now an established major hurricane with little prospect of significant weakening in the next 3 days.

Matthew slowed to a crawl over the weekend, as expected, and lingered over very warm ocean waters that extended to great depth. The long-awaited turn to the north began on Sunday and the storm is now accelerating through the Greater Antilles. Immediate impacts on Haiti are likely to be catastrophic. Haiti only rarely experiences the full force of a northward moving hurricane, with near-record rains expected on south-facing mountain slopes and sustained hurricane force winds. Impacts are also likely to be significant in Jamaica and Cuba. The Bahamas may experience major hurricane impacts if Matthew survives the mountainous islands intact, as expected. Even if weakened, the ingredients of warm oceans, light wind shear and moist air are in place for re-strengthening. The most recent forecasts call for sustained category 3 or 4 intensity over the next 3 days at least (Figure 2). Some temporary relief may come through an eye- wall replacement cycle. But these cycles are incredibly difficult to predict.

Beyond Bermuda, conditions will continue to support a strong hurricane. The latest forecast models have shifted west, increasing the chance of a U.S. landfall between South Florida and North Carolina. The fact that independent forecast centers have all shifted west suggests confidence in this shift, but new forecasts will need careful watch to establish whether this is a temporary change. The further north a potential landfall, the greater chance of Matthew weakening through cooler ocean temperatures and increased shear. However, the area of damaging winds will expand as Matthew tracks north.

Hurricane impacts are possible anywhere from Florida to Maine and interests along the U.S. East Coast should monitor developments. Additional commentaries will be issued as the hurricane forecasts align on the likely scenario.

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Figure 2: Model forecast tracks (left) and intensity (right) for Tropical Storm Matthew at 2000UTC 10/03/16 (NCAR/TCGP). For real-time updated forecasts, please visit: http://www.ral.ucar.edu/hurricanes/realtime/current/

For further information please contact

Dr James Done Roy Cloutier Project Scientist and Willis Research Fellow Catastrophe Analytics National Center for Atmospheric Research Earth System Laboratory Willis Re Inc. P.O. Box 3000, Boulder, CO 80307 7760France Avenue South Suite 450 Minneapolis, MN 55435 Tel: +1 (303) 497-8209 Tel: +1 (952) 841-6652 Email: [email protected] Email: [email protected] Website: http://staff.ucar.edu/users/done Website: http://www.willisresearchnetwork.com/

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